Ron Roberts had a long story to tell. It was as old as the 20th century and crowded with the voices of a vanished country. When you met Ron and listened to him, it was hard to recognise him as a citizen of the new Britain. He was the son of a Boer War veteran and had fought in the Second World War. In his speech and manners, but most of all in his gentleness, he was a rarity. Courtly and self-deprecating, a gentleman. Since Gracie died he's been living on his own. Once a week his two daughters came to visit, and his son-in-law who drove a taxi called in whenever he could.

His flat was on the second floor of a red-brick mansion block, next door to Pentonville Prison on the Caledonian Road. The neighbourhood was one of the poorer parts of Islington. On the other side of the road were several acres of the ugliest urban settlement in the capital: block after block of flats into which Islington's poor had been crammed in the years of the great public housing schemes. Compared to the sad tower blocks, the mansion block where Ron Roberts lived was a model of architectural beauty. It was low-rise with the flats built around a small courtyard. There was a playground for children in the courtyard and several trees that gave the place an air of calm quite at odds with the surrounding neighbourhood.

I drove around the back and parked next to an Ethiopian restaurant. A man standing outside said he'd keep an eye on the car. "The kids here, man, you got to be careful with 'em," he warned.

I had an old friend from South Africa staying with me that weekend: Milton Nkosi, a Soweto-born journalist with whom I had covered the end of apartheid and the election of Nelson Mandela. "Come and see the other London," I'd said to him that morning, as we walked the high street near my home. "It isn't all Starbucks and Waterstone's." As it happened, Milton knew the area. He'd stayed here in the mid Nineties while attending a training course.

"So, baba, we're heading for the townships, your British townships," he'd joked as we drove up past King's Cross. It was a joke, but it pointed up an uncomfortable truth. Where I lived in a leafy suburb of west London, you were as insulated from the realities of marginal Britain as any white South African was from the trials of township life. The nearest council estate was two blocks away. But I had no reason to go there. I suspect I was no different from most of the middle-class residents of my west-London suburb.

I knew that they were out there. Mostly it was a question of following trails left in the night. The glass glistening beside a car with a shattered window; the butt end of a spliff or an empty Special Brew can in the playground. One morning I came outside to find the police surrounding a group of kids in a car. There were five youngsters, aged about 14, and they'd been caught driving a stolen car. I looked inside and saw a tangle of torn wires, a screwdriver, a wrench, some cigarette ends and bits of cardboard ready to be made into a spliff.

Ron Roberts was afraid of kids like that. At 83, and with badly failing eyesight, he rarely ventured out. There was no problem in the block where he lived, but outside the gate it was hard to know who might be waiting to attack you. Unemployment in Islington was nearly twice the London average, and there were estates in the borough that had earned a reputation for violent crime as notorious as any in the country. In the first month of the new millennium there were 404 crimes of "violence against the person" in Islington. When I visited Ron Roberts, it was very easy to see why he would feel afraid to walk the streets on his own.

Yet Islington was not one vast urban wasteland. Anything but. The borough contained some of the most desirable addresses in London, if you had the money. The high crime, the worst GCSE results in London and the high unemployment sat cheek by jowl with neighbourhoods of conspicuous wealth. The other Islington was a place of shiny restaurants and bars - the heartland of New Labour, where Tony Blair and Gordon Brown were reputed to have agreed their political strategy in a restaurant called Granita, a shrine to chic minimalism on thriving Upper Street.

I was sitting in a coffee bar on Upper Street when I came across Ron Roberts's story. The Islington Gazette had reported that Ron had had to spend his life savings to pay for an eye operation. Delays in the NHS could have meant a wait of several months and Ron wasn't in a position to hang about.

Ron had lived in the block for 22 years. For all but the last three months he had shared the flat with his wife Gracie. She died at Christmas. Since then he hadn't bothered much with the small garden he had created on the landing outside the flat. What was the point? he asked himself.

Inside, the flat was conspicuously plush, a place that felt well looked after. The carpeting was thick, and the hand of his late wife could be seen in the velvet drapes of the sitting room and the floral designs of the couches and armchairs. It was comfortable in an old-fashioned way, and in a place of honour at the centre of the mantelpiece was a portrait of Gracie. The woman in the photo was in her fifties with a bouffant hairdo; it had been taken on their wedding day more than 22 years before.

Ron was a distinguished-looking man, with a neat moustache and large brown eyes. For the past two months, since soon after Gracie died, these eyes had been giving him trouble. When he went outside the light blinded him. He would try to cross the road and not see cars coming. When he tried to read the papers the letters and images blurred. When you added to this his angina and his bad hearing, Ron had every reason to feel vulnerable when he walked down the Caledonian Road. He was afraid of the traffic, afraid of strangers, afraid of the gangs who might see an elderly man stumbling home with his pension as an easy target. "Oh, drug gangs. There's lots of gangs around here," he said. "Do you know there was even a couple of gun battles down the road? I don't go out now much. I suppose you'd call me a bit of a recluse."

When Ron went to see his doctor, she told him that he had cataracts and a damaged retina and referred him to a specialist at the Middlesex Hospital. The specialist examined him and said he needed an operation. The problem was that with delays on the NHS it could take weeks if not months before the consultant could attend to him as a public patient. However, if he had the money to go private, then the same consultant could do the operation within a week. Ron asked how much it would cost. The consultant told him he would need more than £2,000 to pay for the treatment. It was everything he had in the bank, his life savings. But he was too scared to wait for the NHS to take care of him. The prospect of going to the shops or the post office and not being able to see where he was walking terrified him. When I met him it was just a week after the operation. The cataracts had been removed but the eye surgeon hadn't been able to do anything about the retina. There had been a small improvement in his sight, but he still struggled to focus on faces and was still scared of going out.

Ron was 83, and the savings he had scraped together over a lifetime amounted to a little over £2,000. He didn't think there was anything wrong with having so little money at the end of a long working life. But he was bitter that he'd had to hand it over, his small nest egg, to pay for treatment he should have had on the NHS.

Ron Roberts was born in 1917 in Tottenham. His father was a veteran of the Boer War, a mounted soldier who'd fought the Afrikaners on the South African veld. When he came home he got a job in a sheet-metal factory and soon after met Ron's mother. She'd been working as a cook at a stately home in Buckinghamshire until she met the returning soldier and became his wife.

It was a happy childhood. At the weekends his father would sit in the garden and mend the children's shoes and give them haircuts. "I always remember him sitting there whistling away to himself. Men don't whistle much any more, do they?" There were 10 children crowded into three bedrooms in their house, with just one gaslight in the kitchen. When things were very tight his mother would go to the Prudential and borrow money. Somehow she managed to keep things going, taking the wages her husband handed over, parcelling out the shillings and pence and keeping creditors from knocking on the door.

Like most boys of his class Ron left school in his early teens. He took up a trade as an apprentice carpenter. This was in 1932 and the western world was in the grip of the worst depression in memory. By 1939 he had married and was the father of a young son. As war approached, he joined the navy ahead of conscription and was trained at Skegness as a signalman. He was sent from there to Lowestoft, where he joined a minesweeping trawler working the coast from Harwich up to Inverness and back. The minesweepers were a crucial part of the country's coastal defences and the ships were in constant danger of attack from German U-boats and aircraft.

There were plenty of near misses. Once he was washed overboard in a storm, another time the boat hit a mine and sank. Luckily they were able to get to the lifeboats and everybody was saved. But he lost many friends in the course of the war. It was something you got accustomed to, he said. I asked him if he could remember the names of his friends from the navy.

"Not these days, son. I think that I'm losing me marbles. With all that's been happening to me, I can't call them back, those names."

But there was camaraderie?

"Oh my, yes, there was. We were great friends. Twenty men who didn't know each other from Adam at the start and we ended up trusting each other completely.'

In 1940 he became one of the lucky few to be selected to travel to America to collect ships given to Britain under the Lease-Lend agreement. There was a long train journey across America from New Jersey to Seattle, before they collected their boat and went down into the Caribbean. There they entered a realm of clear calm water where Ron saw giant turtles, brilliantly coloured sea anemones and bright coral. And once, standing alone at watch, he had seen the shadow of a giant ray emerge from beneath the boat and glide out to the deep. 'Such a sight. My heart missed a beat," he remembered.

From the Caribbean they crossed the Atlantic to West Africa. They stopped at Freetown in Sierra Leone. They were working-class boys who'd never set foot outside Britain before. And now they were watching flying fish skim the surface of the water as they approached the vast green mangroves on the African coast.

On the night the war ended he was sitting on a trawler in Scotland. He doesn't remember any great celebrations, only that the following day a ship was sunk with all hands because a German U-boat captain said he didn't know the war was over.

On leaving the navy, Ron was given a demob suit and nothing else. "Homes for heroes they used to say. Homes for heroes! I was lucky to get any bloody work at all." His wife Alice and young son Roy were living in a rented house in the north London suburb of Hornsey. A second baby was on the way. He changed his trade from carpenter to electrician and went to work for his father's old firm, the Lamp Manufacturing Company. He worked overtime and did odd jobs to earn extra money for his growing family. There were four children in all - two boys and two girls. There was little money, but he and Alice were dedicated to their children. Holidays were a week every year at Yarmouth or Broadstairs, the whole family travelling down by train. On weekends he and his two sons went up to King's Cross and watched the trains travelling in and out of London. At work he began to involve himself in trade union activity, joining the Electrical Trades Union. Around the same time he joined the local Labour Party, to which he has remained loyal all his life. "I wasn't a 'one out, all out' merchant in the union. I didn't believe in that. But getting better conditions for the members, that was what interested me. You've gotta stick up for the working man, you know."

In the early Seventies Alice became ill with cancer and died. He was bereft. Not long afterwards Ron moved jobs to the Primographic Company, which made nameplates for Rover and Ford cars. It was there that he met his second wife, Gracie, who worked as a secretary. They married in 1977 and stayed at the firm until it "downsized" and shifted out of London in the mid Eighties, a victim of the inexorable decline of British manufacturing. Ron was 60 years of age with no job. He'd been given a redundancy payment of £2,000 but had no pension rights. Without the weekly wage to pay his rent, Ron and Gracie were forced to move out of their flat to the council block on the Caledonian Road.

He got a new job at Sadler's Wells Theatre doing maintenance work and manning the stage door. By this time he was well into his 70s. Still, he would work some nights until 11 before shuffling off home. But in the middle of the 1990s Gracie became seriously ill and had to have a triple bypass operation. There was difficulty too with her bronchial tubes. She was placed on a course of medication that had the effect of causing water retention in her legs. They swelled up and left her immobile. In 1995, at the age of 78, Ron finally gave up work to take care of Gracie. "I had to give up. I had to look after her," he said.

Life began to slow down and close in on the couple. They left the flat less and less. One winter day she became ill at home, shaking uncontrollably. He took her to hospital. According to Ron, the doctor said Gracie could be treated as an outpatient. She didn't need to be admitted. He explained that there was a shortage of beds.

"I asked the nurse in charge how we were going to get home. This was in the evening in November and Gracie was dressed in her nightdress. And the nurse says, 'There are plenty of cabs.' I says: 'I know there are, but you try and find one.' I had a hell of a job trying to get her home. That was November 1998. All the following year I was taking her back and forth to the doctor. The last year of her life was the most terrible I could imagine anybody could go through. She didn't get the treatment she deserved. Eventually it got so bad with her legs that she had to be carried up and down the stairs to go to the hospital for outpatient treatment. Then one day I went out shopping and came back to find her lying on the floor with a broken hip. She'd tried to get to the kitchen to get something to eat and had fallen over."

Ron couldn't lift his wife from the floor. He telephoned an ambulance that arrived soon after. But it took the paramedics a long time to persuade Gracie to go to hospital. She was terrified. The broken hip was quickly operated on and Gracie transferred to a recovery ward. When he told me this, the tears began flowing. He recalled how one night the nursing staff had lifted Gracie into her bed; the curtain was drawn and all he could hear was the sound of his wife crying out in pain. It wasn't like her, to cry out. That was why it stayed in his mind so vividly. He went every day and stayed until 9 every night, although it was a long bus ride from the Caledonian Road.

"I could see Gracie was becoming withdrawn, she was going through so much agony. On the last day she was just staring. She couldn't feed herself. They told me she had an infection. That night I said to her, 'I must go, otherwise I won't be able to get home.' She threw her arms up in the air. It was the first movement she made that day. She managed to throw one arm around me and I know that Gracie knew she was dying."

At this point, the old man broke down. "Excuse me," he said, "I am sorry." He started to speak again, with passion, as if pleading with me for understanding. "I didn't know anything life-threatening was happening." At five o'clock the following morning the telephone rang. It was the hospital. We're sorry to tell you that your wife has taken a turn for the worse, they said. He pulled on his clothes and got there in 20 minutes. Gracie was still warm when he arrived. "Had I known there was anything life-threatening, I'd never have left her. You see, that's what she was doing the night before, she was begging me to stay. She was trying to tell me. How can it be that nobody knows she's going to die and she does die? How can that happen?"

He missed her every minute of the day, he told me. Sometimes he picks up the photograph album of their life together. He sits with it in his lap, holding the huge magnifying glass, struggling to give clarity to the blurred images in front of him.

Ron struck me as a fiercely independent man, not someone who would want to live in anybody else's house or be shunted into a retirement home. He was proud of the family he'd raised and of the fact that they visited him frequently. But he was lonely and bitter; he felt the country he'd served in war, where he'd worked and paid his taxes and raised a good family, had failed to deliver for him when he needed it most. The Health Service that could not fix his eyes in time, the hospital that didn't have a bed for his sick wife on a cold November day, the streets where he was afraid to walk and where angry motorists shouted at him - it was all a long way from the great promise of 1945.

My friend Milton had listened to Ron's story with me. Afterwards, as we drove back to west London, he said he couldn't figure out the British attitude to the elderly. He came from a culture where the old were venerated. Grey hair was a sign of wisdom, you listened to what an old man or woman had to say. When he was growing up, his grandparents lived in the family house. They died in that house and were buried from there. It was the same with most of his friends and neighbours. The new South Africa had a hell of a lot lot of problems, but in the matter of how people regard the elderly Milton was convinced it could teach Britain a great deal.

There was something Ron said to me, when he was talking about his childhood. "My mum used to say she was never happier than when the 10 of us were running around the house. But it's all changed, hasn't it? I always ask myself, what's gone wrong?" And then he paused to reflect. An expression of certainty appeared on his face. "You know what's missing now, son? Love, that's it. That's what's missing." That was part of it, all right. Love. It wasn't a word one was used to hearing from people of Ron's generation. They might have felt it, but it was a private word, not to be bandied about in front of strangers. Ron Roberts didn't care for that kind of discretion any longer. He had lost the person he loved most. And his country? The one he'd hoped for when he came home from the war had not materialised. And so he was left to think of the country of childhood. That at least had not been lost to him.

Extracted from 'A Stranger's Eye' (£16.99) by Fergal Keane, published by Viking Penguin on 12 May. Fergal Keane's series 'Forgotten Britain' starts on BBC1 at 10.20pm next Sunday. Readers can order copies of 'A Stranger's Eye' at the reduced price of £14.99 (inc. p&p): send name and address with cheque/postal order payable to 'Book Offer' to: A Stranger's Eye (offer), PO Box 6161, Kettering NN14 4ZG; for credit-card orders, call 01832 733497. Allow 28 days for delivery